When a man lost his nose to cancer, scientists decided to grow him a new one. On his arm.

Experts at University College London are using the man’s bone marrow cells to help him replace the nose that he lost to cancer. Professor Alex Seifalian was reportedly assisting the unnamed 53-year-old survivor develop a new nose, which will be grafted to the man’s arm to develop a natural skin and blood supply, then removed and replaced on the man’s face. Science magazine Focus reports that the nose-growing process is extensive.

The process involves first growing a new nose in the lab, then implanting it on the man’s arm, then ultimately relocating it to the face. “We can make the nose, but we can’t make the skin,” the professor explains.

First, a mold of the patient’s original nose was taken before it’s removal surgery. A second mold is made from the first out of glass. Cells from the patient’s bone marrow are then grown in the lab and added to nose scaffolding built inside the glass mold. It is then placed in a rotating jar, where the temperature is controlled at 98.6 degrees Fahrenheit and the cells grow. After about two weeks, the new nose is ready to be implanted in the man’s arm.

While the nose was growing, a balloon was placed under the skin of the patient’s arm, to slowly expand and stretch the skin, allowing room for the nose implant. Finally, the scaffold — covered in the patient’s cells — is surgically implanted under the stretched arm skin, where it remains for four to six weeks. During that time, it develops a blood supply and molds to the skin. Then, the nose is extracted from the arm and surgically attached to the patient’s face.

Initially, the new nose has no nostrils, because the entire thing is covered in skin. But doctors will later open the nostrils and introduce mucus-membrane-forming cells, called epithelial cells. And voila! A new nose, made from bone marrow, grown on an arm.

The report in Focus was part of a series on the development of regenerative medicine, and techniques used to repair or replace diseased or damaged body parts.